/*
 * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/auth/RFC2617Scheme.java,v 1.10 2004/05/13 04:02:00 mbecke Exp $
 * $Revision: 480424 $
 * $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
 *
 * ====================================================================
 *
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.commons.httpclient.auth;

import java.util.Map;

/**
 * <p>
 * Abstract authentication scheme class that lays foundation for all RFC 2617
 * compliant authetication schemes and provides capabilities common to all
 * authentication schemes defined in RFC 2617.
 * </p>
 * 
 * @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
 */
public abstract class RFC2617Scheme implements AuthScheme {

	/**
	 * Authentication parameter map.
	 */
	private Map params = null;

	/**
	 * Default constructor for RFC2617 compliant authetication schemes.
	 * 
	 * @since 3.0
	 */
	public RFC2617Scheme() {
		super();
	}

	/**
	 * Default constructor for RFC2617 compliant authetication schemes.
	 * 
	 * @param challenge
	 *            authentication challenge
	 * 
	 * @throws MalformedChallengeException
	 *             is thrown if the authentication challenge is malformed
	 * 
	 * @deprecated Use parameterless constructor and
	 *             {@link AuthScheme#processChallenge(String)} method
	 */
	public RFC2617Scheme(final String challenge)
			throws MalformedChallengeException {
		super();
		processChallenge(challenge);
	}

	/**
	 * Processes the given challenge token. Some authentication schemes may
	 * involve multiple challenge-response exchanges. Such schemes must be able
	 * to maintain the state information when dealing with sequential challenges
	 * 
	 * @param challenge
	 *            the challenge string
	 * 
	 * @throws MalformedChallengeException
	 *             is thrown if the authentication challenge is malformed
	 * 
	 * @since 3.0
	 */
	public void processChallenge(final String challenge)
			throws MalformedChallengeException {
		String s = AuthChallengeParser.extractScheme(challenge);
		if (!s.equalsIgnoreCase(getSchemeName())) {
			throw new MalformedChallengeException("Invalid " + getSchemeName()
					+ " challenge: " + challenge);
		}
		this.params = AuthChallengeParser.extractParams(challenge);
	}

	/**
	 * Returns authentication parameters map. Keys in the map are lower-cased.
	 * 
	 * @return the map of authentication parameters
	 */
	protected Map getParameters() {
		return this.params;
	}

	/**
	 * Returns authentication parameter with the given name, if available.
	 * 
	 * @param name
	 *            The name of the parameter to be returned
	 * 
	 * @return the parameter with the given name
	 */
	public String getParameter(String name) {
		if (name == null) {
			throw new IllegalArgumentException("Parameter name may not be null");
		}
		if (this.params == null) {
			return null;
		}
		return (String) this.params.get(name.toLowerCase());
	}

	/**
	 * Returns authentication realm. The realm may not be null.
	 * 
	 * @return the authentication realm
	 */
	public String getRealm() {
		return getParameter("realm");
	}

	/**
	 * Returns a String identifying the authentication challenge. This is used,
	 * in combination with the host and port to determine if authorization has
	 * already been attempted or not. Schemes which require multiple requests to
	 * complete the authentication should return a different value for each
	 * stage in the request.
	 * 
	 * <p>
	 * Additionally, the ID should take into account any changes to the
	 * authentication challenge and return a different value when appropriate.
	 * For example when the realm changes in basic authentication it should be
	 * considered a different authentication attempt and a different value
	 * should be returned.
	 * </p>
	 * 
	 * <p>
	 * This method simply returns the realm for the challenge.
	 * </p>
	 * 
	 * @return String a String identifying the authentication challenge. The
	 *         returned value may be null.
	 * 
	 * @deprecated no longer used
	 */
	public String getID() {
		return getRealm();
	}
}
